MSVC C++ ADL bug?

Question

This code works fine with GCC and Clang. It works fine in MSVC when using a custom type instead of std::chrono::duration. It works fine when using an operator+ over operator*. It works fine with MSVC pre 2018 instead of 2017/2015.

Am I missing anything obvious, or is this just a bug in MSVC? https://godbolt.org/z/EUWV7e

For completeness, here is the test case from the above link:

#include <chrono>

namespace A {
    class Foo {
    public:
        int mCount;
        constexpr explicit Foo(int count) : mCount( count ) {}
    };

    template<class Rep, class Period>
    inline Foo
    operator*(const Foo foo1, const std::chrono::duration<Rep, Period> duration) {
        return Foo(foo1.mCount * duration.count());
    }

    // For testing purposes, this is identical to operator* above.
    template<class Rep, class Period>
    inline Foo
    operator+(const Foo foo1, const std::chrono::duration<Rep, Period> duration) {
        return Foo(foo1.mCount * duration.count());
    }
}

int main() {
    A::Foo foo1(50);

    // This fails to compile for some reason?  Changing the '*' to a '+' works fine however.
    auto foo2 = foo1 * std::chrono::minutes(15);
    return foo2.mCount;
}

Answer 1

I've reported this to the MSVC team at https://developercommunity.visualstudio.com/content/problem/381899/adl-sfinae-bug-in-mvc20152017-when-using-stdchrono.html and they've confirmed it is a bug in MSVC, and has been fixed in the latest release of MSVC2017. Thanks for the discussions!